Edwin b



Patented Jan. 17,1882.

`(Model.)

E. B. BUCKINGHAM.

DEVICE FUR. DRAWING METALTUBES.

u TW wl UNITED STATES PATENT OFFICE. t

EDEIN BUCKINGHAM, OF ,BEOOKLINE ASSIGNOR TO THE AMERICAN -TUBE WORKS, OF BOSTON, MASSACHUSETTS.

`DEVlCE FOR 'DRAWING METL TUBES.

SPECIFICATION forming part of I lretters lPatent No. 252,423, dated January 17, 1882. Application filed January 25, 1877.` Renewed July i4, 1881.. V(Model.)

To all Awhom 'it may concern:

, Be it known that I, EDWIN B. BUCKING- HAM, ofBrooklne, county of Norfolk, and State of Massachusetts, have invented certain new and useful Improvements in Devices for Drawl ing Metal Tubes, `of which the following is a specification.

As is well known,dra\vn metal tubes are manufactured by drawing a 'metal'tube on a `mandrel through a stationary die, and as the working-face of the die is rigid the tubemade 'is of uniform diameter exteriorly. f

The object ot' this inveu tion is to draw metal tubes which sballtaper exteriorly andwhich `can be used for many purposes-as, for instance, hose-pipes, boiler-fines, candle-molds, &c.; and the invention consists'in an expanding die made in parts, each part being constructed ot' metal capable of expanding and to abutor interlock,and in other details, as'hereinafterjshown and described.

In the'acconpanying plateof drawings, Figure 1 is alongitudinal sectiomshoning the irn- E proved combination of tapering mandrel and expanding die, and the mandrel as just entering thedie'to be drawn through' it by the ordinary arrangement and operation of a drawbench; Fig. 2, a similar view to Fig. l, butV showing the rnaudrel as having been drawn through the die. Fig. 3 is a plan view of Fig. 1v. Fig. 4' is a cross-section, on an enlarged scale, ofthe die before use; Fig. 5, a similar section of it after` use. Fig. 6 is a perspective view of adrawn exteriorly taperingmetal tube, and Fig. 7 is a perspective view of a metal tube from which the tube shown in Fig. 6 can be produced. In the drawings, A represents the mandrel, and B the die. The mandrel A tapers in the direction of its length according to the exterior taperof the tube' which it is desired to produce; but otherwise itis formed as usual.

a is the die-opening through which the mandrel'A and the tube on it are to be drawn. This die opening a is shaped to receive the smaller end ofthe mandrel, and thedie is made of such metal as \`vill eXp-and and enlarge or stretch to the increased diameter ot' the mandrel as the mandrel is drawn through the die,.while at the same time it will hug the mandrel with such `tightness as to draw and elongate the tube which is on the mandrel. and shape it eXteriorly to the taper ot' the mandrel, and otherwise reduce and finish it in all the well-known respects of the common drawn metal tube.

For'drawing brass tubes'exteriorl y of a taper,l

a die made only of copper or other proper expanding metal or metals is suitable, and for similarly drawingeopper tubes I usea die which is made in parts, b and o, (see Fig. 4,) which compound constructed die is one of the features of this invention. The part bmakes the working-faceot the die-opening a., and it is made of an alloy of t-in and lead in equal parts; and the part cis a outer metal baud, which surrounds, strengthens, and holds the inner workin g part, b, against rupturefrom the strain on it in the operation Ofdrawinga tube through `its opening a. The outer die. part, c, preferably isy made of copper; but obviously other metals ina-y be used; and, again, preferably it is' madeof a 'metal or metals capable of expanding in proper proportion relative to the eXpan-' :sion of the inner part, and to holding such inner part against rupture in the drawing of a tube through its opening c. The partv b is shouldered'exteriorly and the part c interiorly, and when the two parts are together these shoulders make an abutment and interlock d of the parts, by whichtlie inner part, b, is held against being forced through the outer part, c,

when the die is used, as hereinafter described. The two parts b and c ofthe die preferably are cast or otherwise made separately and f1tted together; but obviously the inner, part may bemade and then the'outer directly upon it.

The die-opening a is bell-shaped at its front or receiving end, f, and countersunk at its rear or delivering end7 g, and 'when the die is in its working position its delivering end g lies against the uprightfaceot' a stationary block, C, with thedie-openingabout and concentric with a hole, It, which extends Ythrough said block. This hole h is of suitable diameter to receive the larger end of the mandrel, and the conntersunk end g of thedie-opening a, which is at the end ofthe die lying against the block C, is such that thebearing of the die against part made or cast the block is beyond the boundary ofthe hole h, all as plainly shown in Fig. l more particularly.

' l is a loose collar of a size to tit the smaller end ofthe taper to the mandrel A and to loosely lit the hole h through head-block C. This collar sets over the end of' the metal tube to be drawn, which is at the smaller end ofthe mandrel, and when the mandrel and die are put into position for the drawing of the tube it is set in the hole h ofthe head-block C,and thus the mandrel is centered in said hole h.

To draw a metal .tube to an exterior taper under this invention, (it being of course understood that tubes and tapering mandrels and expanding dies, all of suitable metal and of suitable relative shape and size, are to b e used together in eac-h instance, (I take the tube which is to be drawn to an exterior taper, and having shouldered or slightly tapered one end -of it, as is well-known in tube-drawing, I place and bring it to a bearing, as usual, on its mandrel. I now place the die on the smaller end ofthe mandrel, and then the loose collar, which latter 1 bring to a bearing over the shouldered end of the tube, which is the end at the smaller end ofthe mandrel, and then [place thesmaller end ot' the mandrel through the headblock opening h and adjust the collar lin said openingh and the die against the head-block in the position described, and all as plainly shown in Fig. 1. The mandrel and tube, with the die, are now in position for the drawing ofthe tube, which is accomplished by attaching the mandrel atits end D to the drawing' mechanism ot' an ordinary draw-bench. As the mandrel and tube are thus drawn through the die-opening a the die expands and enlarges or stretches to the increasing diameter ofthe mandrel, and yet at the same time hugs and binds the tube on the mandrel to such extent as to draw and elongate and shape it to the mandrel, givingit an external taper and `otherwise lfinishing -it as ordinarily in drawing metal tubes. The bell yshape ot' the die-opening gives greater freedom to the entrance ot the mandrel and to the expansion of the metal ofthe die, and also with a given length of die-opening reduces the frictional bearing atthe startot' the die on the tube, and withal admits and secures an increased frictional bearing -proportionate with the increasing work of the die causedby the increasing diameter ot' the mandrel as the mandrel ,V4.tra-ve'ls through the die, and all without in the least degree detracting from the desired acy tion ofthe die.

The countersinking ot' the die-opening a, with the bearing ot' the die against the block C, prevents the die from being drawn-into the opening ofthe head-block by the draw of the mandrel through the die, and this' is insured to a greater degree if said countersinking be so made that the die will have but a small frictional contact with the head-block compared to the full thickness of the 4metal of the die, for the reason, in the tirst case, that the bearing-surface of the die on the tube and mandrel can thereby be so far removed from the opening of the head-block that all the metal 'of the die, if any, which is drawn toward the opening h ot' the head-block, because of the passage of 7o the mandrel through the die, lies within the die and does not enter the said opening; and

for the additional reason, in the second case,

that thedie is rendered thereby freer toopen outwardly than` to be drawn by the mandrel toward said opening.

It isobvious that it' any ot the metal ofthe die be pulled into the opening h such metal proportionately blocks up such opening to the free passage of the mandrel and tube through it, and also would tend to stop the expansion of the die, which shows the importance of the entire countersuuk construction herein described without furtherexplanation, and while neither said countersunk construction nortthe said bell-shape construction of the die'is absolutely essential to the expansive action of the die in the passage of a tapering-mandrel to draw exteriorly a tube to a. taper, yet with either one or both of the said constructions ot' 9o the die the quality ofthe work and the action of the die are measurably improved. v

The choice ot' a metal or metals of which to make a die to expand and operate as described will obviously depend more or less upon the nature ot' metals themselves, their adaptability, either single or in combinations or alloys, for the work, and their capability for being used, as herein described, with the metal4 composing the tube to be drawn, and conse' quently I do not limit myself' to anyparticular metal or metals or alloys of metals for the die.

It may he well to here observe that my improved expansive metal die might be used to draw tubes vto a taper or to draw and uish tapering tubes without a mandrel beingemployed in conjunction with it; but it is preferable, as is obvious, to employ a mandrel, as

described.

' My invention is applicable to drawing tubes exteriorly to a taper, either in the whole o r in a part of their length, and to so drawing tubes Whethertheybestraightor tapering,orstraight in part and tapering in part, or seamless, or brazed, or welded, or made of any metals or combinations or alloys ot' metals.

Having` thus described my invention, what I claim, and desire to secure by Letters Patent, is

' 1. An expanding die, B, in parts b and 0,'

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